/**
 * Copyright (C), 2015-2019, levtime.com
 * FileName: MD5Utils
 * Author:   renhui
 * Date:     2019-01-19 18:00
 * Description:
 * History:
 * <author>          <time>          <version>          <desc>
 * 作者姓名           修改时间           版本号              描述
 */
package com.oneraku.service.utils;

import java.security.MessageDigest;
import java.util.UUID;

/**
 *
 * 〈〉
 *
 * @author renhui
 * @create 2019-01-19
 * @since 1.0.0
 */
public class Md5Utils {
    //十六进制下数字到字符的映射数组
    private final static String[] hexDigits = {"0", "1", "2", "3", "4",
            "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f"};
    public  static String encode(String originString){
        if (originString != null){
            try{
                //创建具有指定算法名称的信息摘要
                MessageDigest md = MessageDigest.getInstance("MD5");
                //使用指定的字节数组对摘要进行最后更新，然后完成摘要计算
                byte[] results = md.digest(originString.getBytes());
                //将得到的字节数组变成字符串返回
                String resultString = byteArrayToHexString(results);
                return resultString.toLowerCase();
            } catch(Exception ex){
                ex.printStackTrace();
            }
        }
        return null;
    }
    /**
     * 转换字节数组为十六进制字符串
     * @param b 字节数组
     * @return
     */
    private static String byteArrayToHexString(byte[] b){
        StringBuffer resultSb = new StringBuffer();
        for (int i = 0; i < b.length; i++){
            resultSb.append(byteToHexString(b[i]));
        }
        return resultSb.toString();
    }

    /** 将一个字节转化成十六进制形式的字符串     */
    private static String byteToHexString(byte b){
        int n = b;
        if (n < 0)
            n = 256 + n;
        int d1 = n / 16;
        int d2 = n % 16;
        return hexDigits[d1] + hexDigits[d2];
    }

    /**
     * 生成指定长度的随机字符串
     *
     * @param
     * @return
     */
    public static String RandomString() {
      return  UUID.randomUUID().toString().trim().replaceAll("-", "").toLowerCase();
    }
}
